Microsoft's new Windows 10 operating system debuts tomorrow, as the longtime leader in PC software struggles to carve out a new role in a world where people increasingly rely on smartphones, tablets and information stored online.

Microsoft's new Windows 10 operating system debuts tomorrow, as the longtime leader in PC software struggles to carve out a new role in a world where people increasingly rely on smartphones, tablets and information stored online.

Microsoft's new Windows 10 operating system debuts tomorrow, as the longtime leader in PC software struggles to carve out a new role in a world where people increasingly rely on smartphones, tablets and information stored online.